N-Pi-Line-Based Image Reconstruction of BPF Algorithms within Standard Spiral Cone Beam CT

In some industrial CT applications, the inspected object is invisible or unknown. It is difficult to always move the object in a uniform speed through the rotational gantry composed with an X-ray source and a detector, such as seismic and oil exploration and so on. In this paper, we prove a generalized backprojection-filtration(BPF) formula within standard helix cone beam CT to get the sufficient projection datum and the accurate reconstructed image. According to the image,we can know what it is. So we perhaps need more scanning datum to perform exact image reconstruction, here a major implication of n-pi-line is that it can be applied for BPF algorithm reconstruction. By reducing the helix pitch (the helix pitch completely depends on the rotation angle ), we get more datum from n-pi-segment in helix cylindrical object support. So we employ all n-pi-line to fill the region-of-interest(ROI) and gain more exact image, and use 3D Shepp-Logan phantom to simulation the result.